A 213 KB PDF dedicated to the 2SC3657. By Japanese JIS convention the 2SC prefix denotes an NPN bipolar transistor; the file name gives only this number. Content is most likely a component datasheet with ratings tables, characteristic graphs and the outline drawing, even though it is indexed under schematics. Use it to confirm lead assignment, check breakdown voltage and dissipation against the circuit, and evaluate cross-reference parts. Any PDF reader opens it without special software.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @cyberlanelectonik. Enginerys does not host this file.
How to open a .pdf file
The standard format for schematics, block diagrams, power-sequence charts and service manuals.